1. Field of the Invention
The present invention relates to a card connector, and more particularly to a so-called push-push type card connector in which positioning of a card to a card set position, and ejection of the card from the card set position are alternately conducted by repeating an operation of pushing the card.
2. Description of the Prior Art
Conventionally, card connectors configured in the following manner are known. When an initial pushing operation is conducted on a card inserted into a card insertion space of a case, a slider is pushed from a standby position to a pushed position, and the slider which reaches the pushed position is locked to the position so that the card is positioned to a card set position. By contrast, when a second pushing operation is conducted on the card, the locked state of the slider is canceled, and the card is retracted together with the slider to be ejected. In some of such card connectors, the functions of locking the slider and canceling the locked state are realized by a cam mechanism. The cam mechanism is configured as shown in FIGS. 12 and 13.
FIG. 12 is a schematic perspective view showing a cam body 20 of a cam mechanism 10 which is employed in a conventional card connector, and FIG. 13 is a longitudinal side section view showing main portions of the cam mechanism 10.
The cam mechanism 10 comprises the cam body 20, and an engagement pin 40 which is formed by bending an elastic wire member. A loop groove 21 is formed in the cam body 20. The loop groove 21 comprises: a forward path 22; a return path 23; a protruding engagement portion 24 which is formed between the paths; a lead-in path 25 which elongates from a forward-path end portion 22a to the engagement portion 24; and an escape path 26 which elongates from the engagement portion 24 to a return-path start portion 23a. The loop groove 21 is formed into a slender heart shape as a whole, and the lead-in path 25 and the escape path 26 form a heart-shape recess.
In the cam mechanism 10, the cam body 20 is resiliently urged in the direction of the arrow A of FIG. 12 by an urging force indicated by the arrow A. By contrast, a basal portion (not shown) of the engagement pin 40 is swingably supported at a constant position, and an engagement end 41 at the tip end of the pin is always fitted into the loop groove 21. At the initial position, the engagement end 41 is positioned in a junction 27 of the start portion of the forward path 22 and the end portion of the return path 23 (this state is not shown in the figures). The engagement pin 40 is always elastically pressed against a bottom face of the loop groove 21 by the elasticity of the pin itself or by a spring piece which is not shown.
When, in a state where the engagement end 41 of the engagement pin 40 is positioned in the junction 27 of the loop groove 21, the cam body 20 is pushed against the urging force A, the engagement end 41 moves along the forward path 22 of the loop groove 21 to reach the forward-path end portion 22a. When the pushing force is canceled at this timing, the cam body 20 is pushed back by the urging force A, so that the engagement end 41 moves along the lead-in path 25 and is then engaged with the engagement portion 24 as shown in FIG. 12. When the cam body 20 is then pushed against the urging force A, the engagement end 41 moves along the escape path 26 to reach the return-path start portion 23a. When the pushing force is canceled at this timing, the cam body 20 is pushed back by the urging force A, so that the engagement end 41 moves along the return path 23 and then returns to the junction 27.
In the conventional card connector, the cam body 20 is disposed integrally with a slider (not shown) which is longitudinally movably attached to a case (not shown) forming a card insertion space, and the urging force A is applied to the slider. The slider is configured so that it is pushed by a card which is inserted into the card insertion space, to be moved from a standby position to a pushed position corresponding to the card set position. Then, the engagement end 41 is engaged with the engagement portion 24 as shown in FIG. 13, whereby the slider is locked to the pushed position. Therefore, the card is positioned to the card set position by the first card pushing operation, and terminals of the card are in contact with contacts disposed in the case so as to make electrical connections therebetween. By contrast, when, in the state where the slider is locked, the slider is pushed by the card, the engagement end 41 moves along the escape path 26 to be disengaged from the engagement portion 24 as described above, so that the locked state of the slider is canceled. Then, the engagement end 41 returns via the return path 23 to the junction 27, whereby the card is ejected. Therefore, the locked state of the slider is canceled by the second card pushing operation, and the card which has been positioned to the card set position is ejected.
As seen from FIGS. 12 and 13, the cam mechanism 10 which is employed in the conventional card connector comprises a stepped surface 31 in the boundary between the escape path 26 of the loop groove 21 of the cam body 20 and the return path 23. After the engagement end 41 moves along the escape path 26 and reaches the return-path start portion 23a, during retraction of the cam body 20, the stepped surface 31 slides in contact with the engagement end 41, whereby the engagement end 41 is retained in the return path 23, so that the engagement end 41 is prevented from reversely moving to a position a where the engagement end is to be engaged with the engagement portion 24. A bottom face 26a of the escape path 26 is formed as a horizontal surface. In the second card pushing operation, therefore, the engagement end 41 which is elastically pressed against the horizontal bottom face 26a of the escape path 26 by the function of the spring piece slides on the bottom face 26a and passes over the stepped surface 31 to reach the return-path start portion 23a. 
A prior art example discloses a structure in which a cam mechanism which is similar to the cam mechanism 10 is employed so that a slider is locked or the locked state is canceled (for example, see Japanese Patent No. 3,083,778).
Another prior art example discloses a structure in which a cam mechanism which is similar to the cam mechanism 10 is employed so that a slider is locked or the locked state is canceled. The other prior art example discloses also a structure in which means for directly engaging an elastic lock piece of the slider with a notch of a card is employed as means for positioning the card to a card set position, and an engagement end of an engagement pin of the cam mechanism is elastically pressed against a bottom face of a loop groove on the side of a cam body by a spring piece formed by stamping and raising a metal cover constituting a case (for example, see Japanese Patent Application Laying-Open No. 2002-134224).